From owner-freebsd-hackers Sun Sep 12 0:16: 4 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from jason.argos.org (a1-3a123.neo.rr.com [24.93.180.123]) by hub.freebsd.org (Postfix) with ESMTP id 4C0131525C for ; Sun, 12 Sep 1999 00:15:57 -0700 (PDT) (envelope-from mike@argos.org) Received: from localhost (mike@localhost) by jason.argos.org (8.9.1/8.9.1) with ESMTP id DAA23162; Sun, 12 Sep 1999 03:15:42 -0400 Date: Sun, 12 Sep 1999 03:15:42 -0400 (EDT) From: Mike Nowlin To: Kevin Day Cc: hackers@FreeBSD.ORG Subject: Re: damn ATX power supplies... In-Reply-To: <199909120658.BAA43940@celery.dragondata.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > Yeah, you're supposed to tie PE low when you want power... However, in a > system I'm working with now, we've discovered that some inexpensive ATX > power supplies don't expect to have PE come up immediately when they're > given power. If you see the symptom that all the LED's on your system dim > about 1-2 seconds after you give the power supply AC for a second or so, you > need to make a small timer circuit to wait 5 seconds or so before turning > the PE line on. Related info: if you have external devices (printer, and especially modem) attached, try turning them off and then applying pwr to the computer. In some of the cheaper systems we have around here, the modem needs to be turned off, or the computer flashes on for a second and then turns off... (486 boards, AT power supplies)... I did a bit of measuring, and on these cheap ones, some of the +12V from the modem serial lines gets leaked back into the power supply, causing it to wig out... --mike To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message